How can I view a texture on a model?
Sometimes while importing an obj model, the uvs get messed up, which eliminates all simple answers. If not, there is an easy way.


import the model into Blender.
Switch from object mode, to texture paint mode.
Switch to textured view. (or material view, depending on how you like it and your circumstances.)


The most common error, besides the UVs being messed up, is the material not working in Blender. If you are simply texture painting, this is easy to fix.
Simply,


Add a material. (or click use nodes on the current one).
Load the texture into the material.


Now it should show up.

This same concept applies to most model types.
Here is an illustration using a .3ds model I got from www.archibase.net.
In this example, the uv map was already there how it was meant to be, I just needed to adjust the material. If I would have re-unwrapped, that would have ruined the intended position of the texture.